JP2003014438A - Substrate inspection device and substrate inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate inspection device and substrate inspection method capable of surely suppressing the increase in size of the device accompanied by the increase in size of a substrate. SOLUTION: This device comprises optical systems 26 and 27 for forming the image of a partial area in the surface to be inspected of the substrate 11; a rotating means 16 for rotating the substrate at 90 deg. intervals around an axis 12a passing the center of the surface to be inspected and perpendicular to the surface to be inspected, and parallel moving means 14 and 15 for relatively moving the substrate and the optical systems in parallel along the surface to be inspected while stopping the rotation of the substrate by the rotating means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate inspection device and a substrate inspection method used for inspecting a semiconductor wafer or a liquid crystal substrate in a process of manufacturing a semiconductor element or a liquid crystal display element.

[0002]

2. Description of the Related Art As is well known, in the manufacturing process of semiconductor elements and liquid crystal display elements, an exposure step of printing a circuit pattern formed on a mask (reticle) on a resist film and an exposed or unexposed portion of the resist film are performed. A circuit pattern (resist pattern) is transferred to the resist film through a dissolving development process, and etching or vapor deposition is performed using this resist pattern as a mask (processing process), so that a predetermined pattern is formed immediately below the resist film. The circuit pattern is transferred to the material film (pattern forming step).

Then, in order to form another circuit pattern on the circuit pattern formed on the predetermined material film, the same pattern forming process is repeated. By repeatedly executing the pattern forming process many times, circuit patterns of various material films are laminated on a substrate (semiconductor wafer or liquid crystal substrate) to form a circuit of a semiconductor element or a liquid crystal display element.

By the way, if there is a defect in the resist pattern in the above manufacturing process, processing is performed according to the defect, resulting in a defective product. The defective portion is, for example, a portion where the pattern cross-sectional shape is changed due to the defocus of the exposure device, a portion where the resist film thickness is changed, or a portion where a foreign matter or a scratch is attached. Therefore, the defect inspection of the resist pattern has been conventionally performed.

In some cases, the resist pattern in a certain pattern forming process is not accurately superimposed on the circuit pattern (hereinafter referred to as "base pattern") formed in the immediately preceding pattern forming process. If the pattern formation process is continued and the material film is processed through the resist pattern, an inaccurate circuit pattern with the underlying pattern is formed, resulting in a defective product (element with poor performance or element that does not function). Will end up. Therefore, conventionally, an overlay inspection of a resist pattern with respect to a base pattern has been performed.

Incidentally, the inspection (defect inspection or overlay inspection) on the substrate on which the resist pattern is formed
At this time, the substrate is movable in two directions orthogonal to each other in the horizontal plane.
It is mounted on an axial stage and moved with respect to a fixed inspection optical system. Then, when the inspection target portion of the substrate is positioned within the field of view of the inspection optical system, an image of the inspection target portion is captured using an image sensor such as a CCD camera, and image processing is performed on the obtained image signal. Thus, the board is inspected.

[0007]

However, the above-mentioned conventional technique has a problem in that the size of the biaxial stage must be increased as the size of the substrate is increased in order to efficiently carry out various processing steps. When a biaxial stage is used, in order to be able to position any part of the substrate within the field of view of the inspection optical system, the movable range (stage stroke) of the biaxial stage is at least a range corresponding to the vertical and horizontal dimensions of the substrate. Must be secured. Therefore, the size of the biaxial stage is at least twice as large as the vertical and horizontal dimensions of the substrate.

With a wafer of 300 mmΦ, which is the main force today, at least the stroke of the stage is 600 m.
A large size of m × 600 mm is required. On the other hand, for a 200 mmΦ wafer one generation ago, the required stage stroke is 400 mm × 400 mm. Therefore, when the diameter of the wafer is increased by 1.5 times, the area must be increased by 2.25 times.

As a result of the large size of the two-axis stage,
A device equipped with a two-axis stage and an inspection optical system also becomes large in size, and in some cases, a clean room must be enlarged. Increasing the size of the clean room is not preferable because it increases the cost. Further, if the size of the clean room is increased, it becomes difficult to keep the cleanliness high, and it is difficult to meet the demand for improvement of the cleanliness accompanying the miniaturization of the circuit pattern, which is not preferable.

Even if the substrate is fixed and the inspection optical system is mounted on the biaxial stage, the same problem as described above occurs. Further, arranging the movable portion, which is a dust source, on the upper side of the wafer, which does not like the adhesion of foreign matter, is a problem before the improvement of cleanliness. An object of the present invention is to provide a substrate inspection device and a substrate inspection method that can reliably suppress the increase in size of the device due to the increase in size of the substrate.

[0011]

A substrate inspection apparatus of the present invention includes an optical system (26, 27) for forming an image of a partial area on a surface to be inspected of a substrate (11) and a center of the surface to be inspected. And a rotation means (16) for rotating the substrate at intervals of 90 degrees about an axis (12a) perpendicular to the surface to be inspected, and the substrate and the optical system while the rotation of the substrate by the rotation means is stopped. And parallel translation means (14, 15) for relatively performing parallel translation along.

The substrate inspection method of the present invention comprises the steps of rotating the substrate at 90-degree intervals with the axis passing through the center of the surface to be inspected of the substrate and perpendicular to the surface to be inspected as a rotation axis, and stopping the rotation of the substrate. And a step of relatively moving the optical system for forming an image of a partial area on the surface to be inspected and the substrate in parallel along the surface to be inspected.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

(First Embodiment) The first embodiment of the present invention is as follows.
It corresponds to claim 1, claim 2, and claim 4. As shown in FIG. 1, the substrate inspection apparatus 10 of the first embodiment drives a wafer holder 12 that holds a semiconductor wafer 11 (disk-shaped substrate), which is an object to be inspected, in a horizontal state by vacuum suction, and the wafer holder 12. The holder drive unit (14 to 16) and the wafer inspection unit (17 to 2) that inspects the surface of the semiconductor wafer 11
9) and. The board inspection apparatus 10 is also provided with a focusing section (30 to 41). Wafer inspection department
(17-29) and the focusing section (30-41) are fixed above the semiconductor wafer 11.

Before specifically explaining the substrate inspection apparatus 10, the semiconductor wafer 11 held by the wafer holder 12 will be described. As shown in FIG. 2, a rectangular shot area 1 is formed on the surface (inspected surface) of the semiconductor wafer 11.
A plurality of 1a are arranged two-dimensionally along the x-direction and the y-direction which are coordinate axes in the wafer surface. The x direction and the y direction are orthogonal to each other. In addition, each shot area 11a
The circuit patterns 11b and 11c are formed on.
Usually, the linear directions of the circuit patterns 11b and 11c are parallel to the x direction or the y direction.

Further, a notch 11d or an orientation flat (not shown) is provided around the semiconductor wafer 11.
Indicators such as are provided. When the semiconductor wafer 11 is placed on the wafer holder 12, the notch 11d or other index is used as an outer shape reference indicating the orientation of the semiconductor wafer 11 (the orientation of the xy coordinate system). In mounting the semiconductor wafer 11 on the wafer holder 12, a pre-alignment system (not shown) is placed so that the center 11e of the surface of the semiconductor wafer 11 is located on the central axis 12a (FIG. 1) of the wafer holder 12. Is adjusted by. This central axis 1
2a passes through the center of the wafer holder 12 in the vertical direction (z
Direction) is an axis parallel to.

Next, the structure of the substrate inspection apparatus 10 will be described. Here, the wafer inspecting unit (17 to 29), the holder driving unit (14 to 16), and the focusing unit (30 to 41) in this order,
The configuration will be described. The wafer inspection unit (17 to 29) for inspecting the surface of the semiconductor wafer 11 includes a light source 17, a collector lens 18, a filter 19, a relay lens 20, an aperture stop 21, a relay lens 22, and a visual field arranged along the axis 10a. Diaphragm 23, condenser lens 24, half mirror 25,
It is composed of an objective lens 26, an imaging lens 27, a two-dimensional image pickup device 28 arranged along the axis 10b, and an image processing unit 29 connected to the two-dimensional image pickup device 28.

The half mirror 25 is arranged on the axis 10b (afocal system between the objective lens 26 and the imaging lens 27). The image processing unit 29 is also connected to holder drive units (14 to 16) described later. Incidentally, the shaft 10b
A dichroic mirror 35 of a focusing unit (30 to 41) described later is also arranged above. In the wafer inspection unit (17 to 29) described above, the light from the light source 17 is condensed by the collector lens 18, and the filter 19, the relay lens 20, the aperture stop 21, the relay lens 22 and the field stop 2 are collected.
3, incident on the half mirror 25 through the condenser lens 24. Then, it is reflected by the half mirror 25, and is irradiated onto the surface of the semiconductor wafer 11 via the dichroic mirror 35 and the objective lens 26.

At this time, the illumination light for the surface of the semiconductor wafer 11 is applied only to a predetermined visual field range (partial area) within a predetermined incident angle range. The incident angle range of illumination light is
It is determined by the aperture diameter of the aperture stop 21 arranged on a plane conjugate with the pupil 26a of the objective lens 26. The field range of the illumination light is determined by the diaphragm diameter of the field diaphragm 23 arranged on the surface conjugate with the surface of the semiconductor wafer 11.

The light reflected, diffracted, and scattered by the circuit patterns 11b and 11c (see FIG. 2) formed on the surface of the semiconductor wafer 11 is condensed by the objective lens 26 and is reflected by the dichroic mirror 35 and the half mirror 25. The light is transmitted and guided to the imaging lens 27, and an image is formed on the imaging surface of the two-dimensional imaging device 28. At this time, the circuit pattern 11 on the surface of the semiconductor wafer 11 is formed on the image pickup surface of the two-dimensional image pickup device 28.
An enlarged image of b and 11c (hereinafter referred to as "pattern image") is formed. Hereinafter, the area of the surface of the semiconductor wafer 11 corresponding to the image pickup surface of the two-dimensional image pickup device 28 is referred to as an “image pickup area”.

In the two-dimensional image pickup device 28, the pattern image formed on the image pickup surface is photoelectrically converted for each pixel, and an image pickup signal corresponding to the light intensity (brightness) of the pattern image is output to the outside. The image pickup signal from the two-dimensional image pickup device 28 is converted into a digital signal and taken in by the image processing unit 29 as a pattern image. The pattern image is an image of a portion of the surface of the semiconductor wafer 11 which is positioned within the above-mentioned imaging region.

Here, it is assumed that the plurality of pixels of the two-dimensional image pickup device 28 are arranged in a substantially square lattice pattern in the first embodiment. Further, of the array directions of the pixels of the two-dimensional image pickup device 28, the horizontal direction is the U direction and the vertical direction is the V direction. The U direction and the V direction are orthogonal to each other. Further, when the coordinates u, v in the imaging area on the stage are taken in the directions corresponding to the array directions U, V of the respective pixels, in the substrate inspection apparatus 10, the axis 10
Since b is not deflected halfway, the u and v directions are parallel to the horizontal plane.

Next, the holder drive section (14-16) for driving the wafer holder 12 will be described. Holder drive
(14 to 16) are u drive unit 14 and v drive unit 15 for translating the wafer holder 12 in parallel in the horizontal plane (uv plane).
And a rotation drive unit 16 for rotating the wafer holder 12 around the central axis 12a, and the wafer holder 12 in the vertical direction (z
Direction) and a z drive unit (not shown).

By the holder driving section (14-16), the semiconductor wafer 11 held by the wafer holder 12 is rotated or moved while maintaining the horizontal state. As described above, since the center 11e of the surface of the semiconductor wafer 11 is located on the center axis 12a of the wafer holder 12, the rotation of the semiconductor wafer 11 is performed around the center 11e of the semiconductor wafer 11.

Further, the u drive unit 14 includes the wafer holder 12
Is moved in the u direction. When the wafer holder 12 is moved in parallel by the u drive unit 14, the circuit pattern 1 formed on the semiconductor wafer 11 on the wafer holder 12
Since 1b and 11c (see FIG. 2) move in parallel in the u direction,
The pattern image formed on the image pickup surface of the two-dimensional image pickup device 28 also moves in parallel in the u direction.

Similarly, the v-driving section 15 is used for the wafer holder 1
2 is moved in the v direction. When the wafer holder 12 is moved in parallel by the v drive unit 15, the circuit patterns 11b and 11c (see FIG. 2) formed on the semiconductor wafer 11 on the wafer holder 12 are moved in parallel in the v direction, and the image pickup surface of the two-dimensional image pickup device 28 is moved. The upper pattern image also moves in parallel in the v direction.

The orientation of the semiconductor wafer 11 on the wafer holder 12 (the orientation of the xy coordinate system) is determined by the semiconductor wafer 11
2 is adjusted by using the notch 11d, etc., and is positioned on the wafer holder 12 so as to be in the state of FIG. 2 so as to be aligned with the uv coordinate system by the u driving unit 14 and the v driving unit 15. Therefore, the circuit patterns 11b and 11c formed in each shot area 11a of the semiconductor wafer 11
The linear direction of FIG. 2 is parallel to the u direction or the v direction of the uv coordinate system by the u driver 14 and the v driver 15.

On the other hand, the rotation drive unit 16 is used for the wafer holder 1.
2 is rotated at 90 degree intervals. Rotation drive unit 1
When the wafer holder 12 is rotated by 6, the semiconductor wafer 11 on the wafer holder 12 also rotates at intervals of 90 degrees. That is, the semiconductor wafer 11 can be rotated in four states shown in FIGS. 2, 3, 4, and 5.

In these four states (FIGS. 2 to 5), the linear directions of the circuit patterns 11b and 11c formed on the semiconductor wafer 11 are always in the u driving section 14,
It is parallel to the u direction or the v direction of the uv coordinate system by the v drive unit 15. For example, in FIG. 2, the circuit pattern 11b parallel to the u direction becomes parallel to the v direction when rotated by 90 degrees (FIG. 3), and becomes parallel again to the u direction when rotated by 90 degrees (FIG. 4), and further 90 degrees. When it rotates (FIG. 5), it becomes parallel to the v direction again.

In the four states (FIGS. 2 to 5), the linear direction of the pattern image formed on the image pickup surface of the two-dimensional image pickup device 28 is always the arrangement direction of a plurality of pixels, that is, the horizontal direction. It is parallel to the direction (u direction) or the vertical direction (v direction). In the substrate inspection apparatus 10 of the first embodiment, the u drive unit 14, when the rotation of the rotation drive unit 16 is stopped,
Since the v-driving unit 15 performs the parallel movement, the uv driving unit 14 and the v-driving unit 15 perform the parallel movement regardless of the four rotation states of the semiconductor wafer 11 (FIGS. 2 to 5). Orientation of semiconductor wafer 11 with respect to the coordinate system (x
The orientation of the y coordinate system) is kept constant.

Further, the board inspection apparatus 10 of the first embodiment.
, The movable range Δu, Δv (stage stroke) of the wafer holder 12 by the u drive unit 14 and the v drive unit 15
Is set to be approximately the same as the radius r of the semiconductor wafer 11, as shown in FIG. Therefore, when the parallel movement by the u drive unit 14 and the v drive unit 15 is performed within the above range Δu, Δv while the rotation by the rotation drive unit 16 is stopped, one An arbitrary portion in the quadrant (hatched range in FIG. 6) can be positioned within the above-mentioned imaging region, and a pattern image can be captured.

Here, the orientation (direction of the xy coordinate system) of the semiconductor wafer 11 is uv by the u driver 14 and the v driver 15.
As shown in FIG. 7, the four quadrants of the semiconductor wafer 11 are referred to as “first quadrant 51”, “second quadrant 52”, and “third quadrant 53” with reference to the state (FIG. 2) that coincides with the coordinate system. , "4th
We will call it quadrant 54 ". The first quadrant 51 is (+ x, +
quadrant in the (y) direction, the second quadrant 52 is the quadrant in the (-x, + y) direction, the third quadrant 53 is the quadrant in the (-x, -y) direction, and the fourth quadrant 54 is the (+ x , -Y) direction quadrant.

In the substrate inspection apparatus 10 of the first embodiment, when the semiconductor wafer 11 is stopped in the rotating state of FIG.
When translated in the above range Δu, Δv (FIG. 6),
It is possible to position an arbitrary portion of the first quadrant 51 of the semiconductor wafer 11 within the imaging region and capture the pattern image.

Similarly, when the semiconductor wafer 11 is stopped in the rotating state of FIG. 3, the above ranges Δu, Δv (FIG. 6) are obtained.
When moved in parallel, the second quadrant 5 of the semiconductor wafer 11
An arbitrary portion of 2 can be positioned within the imaging area to capture the pattern image. Furthermore, the semiconductor wafer 1
When 1 is stopped in the rotation state of FIGS. 4 and 5, if it is translated within the above range Δu, Δv (FIG. 6), any one of the third quadrant 53 and the fourth quadrant 54 of the semiconductor wafer 11 can be moved. The portion can be positioned within the imaging area to capture the pattern image.

At the end of the description of the structure of the substrate inspection apparatus 10, the focusing parts (30 to 41) will be described. The focusing unit (30 to 41) is a light source 3 arranged along the axis 10c.
0, collector lens 31, AF slit 32, half mirror 33, condenser lens 34, dichroic mirror 35, and relay lens 3 arranged along the axis 10d.
6, a pupil division prism 37, a relay lens 38, a cylindrical lens 39, a one-dimensional image pickup device 40, and an AF processing unit 41 connected to the one-dimensional image pickup device 40.

The half mirror 33 is also arranged on the axis 10d. The axes 10c and 10d are orthogonal to each other, and the axis 1
0c is orthogonal to the axis 10b described above. Pupil division prism 37
Are arranged at positions conjugate with the pupil 26a of the objective lens 26. The AF processing unit 41 includes the holder driving unit (1
4 to 16). The light source 30 emits autofocus light (AF light) such as infrared light having a wavelength different from that of the light source 17 of the wafer inspection unit (17 to 29) described above.

In this focusing section (30-41),
The AF light from the light source 30 includes a collector lens 31, an AF slit 32, a half mirror 33, and a condenser lens 34.
After passing through, the light is reflected by the dichroic mirror 35 and is irradiated onto the surface of the semiconductor wafer 11 via the objective lens 26. At this time, on the surface of the semiconductor wafer 11,
The slit image is projected in a direction inclined by 45 degrees with respect to the xy coordinate system.

Then, the slit-shaped AF light reflected on the surface of the semiconductor wafer 11 is condensed again by the objective lens 26, and the dichroic mirror 35 and the condenser lens 3 are formed.
The light enters the half mirror 33 via 4 and is reflected there. Further, the slit-shaped AF light reflected by the half mirror 33 is incident on the cylindrical lens 39 via the relay lens 36, the pupil division prism 37, and the relay lens 38, where the spread in the longitudinal direction is compressed, and then one-dimensional. Image sensor 4
An image is formed on the image pickup plane of 0.

Since the AF light is split into two by the pupil splitting prism 37, an image resulting from the two AF lights split by the pupil splitting prism 37 is present on the image pickup surface of the one-dimensional image pickup device 40. It is formed. Therefore, the AF processing unit 4
1, the amount of deviation in the z direction between the surface of the semiconductor wafer 11 and the object plane of the objective lens 26 is detected based on the distance between the two images formed on the image pickup surface of the one-dimensional image pickup device 40, and the wafer holder 12 The amount of movement in the z direction is determined, and a z drive unit (not shown) is controlled. As a result, the wafer holder 12 can be set in focus.

The above A by the focusing unit (30 to 41)
The F control is appropriately executed at the time of the image capturing operation in the board inspection device 10 of the first embodiment. Next, an image capturing operation in the board inspection apparatus 10 of the first embodiment will be described. Here, an example in which an entire image of the surface of the semiconductor wafer 11 is captured in order to perform a defect inspection on the semiconductor wafer 11 will be described.

The semiconductor wafer 11 is transferred by a transfer system (not shown).
Is placed on the wafer holder 12, and the center 11 of the wafer 11 is
When e is positioned on the central axis 12a of the wafer holder 12 and the orientation (direction of the xy coordinate system) of the semiconductor wafer 11 matches the uv coordinate system (state of FIG. 2), the image processing unit 29 The image capturing operation is executed according to the procedure of the flowchart shown in FIG.

In step S1, the image processing unit 29 performs parallel movement by the u driving unit 14 and the v driving unit 15 within the above range Δu, Δv (FIG. 6), and the semiconductor wafer 11
The pattern images of the first quadrant 51 are sequentially captured (FIG. 9A). The pattern image of the first quadrant 51 obtained at this time becomes image data in the uv coordinate system. Finally, image data in the xy coordinate system is required, so step S
The image data in the uv coordinate system of the first quadrant 51 captured in 1 is (u, v) →
Coordinate conversion of (x, y) = (+ u, + v) is performed.

Next, in step S2, the image processing unit 29 determines whether or not the image capturing for the four quadrants (51 to 54) of the semiconductor wafer 11 has been completed, and there is a quadrant in which no image has been captured yet. If there is (step S2
Is N), the process proceeds to step S3. At this stage, since the image of the second quadrant 52 of the semiconductor wafer 11 is captured, the process proceeds to step S3.

In step S3, the image processing unit 29
Measures the xy positions of the two index marks 61, 62 located on the boundary between the first quadrant 51 and the second quadrant 52.
Then, in step S4, the semiconductor wafer 11 is
It is rotated by 0 degree (state of FIG. 3 and FIG. 9B). next,
The image processing unit 29 again measures the xy positions of the index marks 61 and 62 whose xy positions have been measured previously (step S
5) The rotation error of the semiconductor wafer 11 and the position shift (position correction amount) of the center 11e are calculated (step S6), and the rotation error of the semiconductor wafer 11 and the position shift of the center 11e are calculated based on the obtained position correction amount. Is corrected (step S
7).

After that, the image processing unit 29 determines in step S1.
Returning to, the pattern images of the second quadrant 52 of the semiconductor wafer 11 are sequentially captured (FIG. 9B). The pattern image of the second quadrant 52 obtained at this time becomes image data in the uv coordinate system. The image data of the second quadrant 52 in the uv coordinate system has (u,
v) → (x, y) = (− v, + u) coordinate transformation is performed.

Next, the image processing unit 29 determines the semiconductor wafer 1
In order to capture the image of the first quadrant 53 (N in step S2), the process proceeds to step S3 in the same manner as above, and the two index marks 63 located on the boundary line between the second quadrant 52 and the third quadrant 53. , 64 xy positions are measured.
Then, in step S4, the semiconductor wafer 11 is
It is rotated by 0 degree (state of FIGS. 4 and 9C), and the xy positions of the index marks 63 and 64 are measured again (step S
5) The position correction amount of the semiconductor wafer 11 is calculated (step S6), and the rotation error of the semiconductor wafer 11 and the position axis shift of the center 11e are corrected based on the obtained position correction amount.
(Step S7).

After that, the image processing section 29 determines in step S1.
Then, the pattern images of the third quadrant 53 of the semiconductor wafer 11 are sequentially captured (FIG. 9C). The pattern image of the third quadrant 52 obtained at this time becomes image data in the uv coordinate system. In the image data of the third quadrant 53 in the uv coordinate system, (u,
v) → (x, y) = (− u, −v) coordinate transformation is performed.

Next, the image processing unit 29 determines the semiconductor wafer 1
In order to capture the image of the first quadrant 54 (N in step S2), the process proceeds to step S3 similarly to the above, and two index marks 65 located on the boundary line between the third quadrant 53 and the fourth quadrant 54. , 66 xy positions are measured.
Then, in step S4, the semiconductor wafer 11 is
It is rotated by 0 degree (state of FIG. 5 and FIG. 9D), and the xy positions of the index marks 65 and 66 are measured again (step S
5) The position correction amount of the semiconductor wafer 11 is calculated (step S6), and the rotation error of the semiconductor wafer 11 and the position axis shift of the center 11e are corrected based on the obtained position correction amount.
(Step S7).

After that, the image processing unit 29 determines in step S1.
Then, the pattern images of the fourth quadrant 54 of the semiconductor wafer 11 are sequentially taken in (FIG. 9 (d)). The pattern image of the fourth quadrant 54 obtained at this time becomes image data in the uv coordinate system. In the image data of the fourth quadrant 54 in the uv coordinate system, (u,
The coordinate conversion of v) → (x, y) = (+ v, −u) is performed.

As described above, the four quadrants (5
Since the image capturing for 1 to 54) is completed, the image processing unit 29 proceeds from step S2 to step S8. In this step S8, the above-mentioned coordinate conversion is applied to the image data in the uv coordinate system of the four quadrants (51 to 54), and the x of the four quadrants (51 to 54) obtained.
The pattern image is reconstructed based on the image data in the y coordinate system, and the image capturing operation is completed.

The reconstruction of the pattern image in step S8 is carried out by the information on the rotation direction (quadrant) of the semiconductor wafer 11 by the rotation driving unit 16 and the u driving unit 14, v driving unit 1.
5 based on the information on the horizontal position (u, v) of the semiconductor wafer 11 according to the step 5. As a result, a pattern image of the entire semiconductor wafer 11 in the xy coordinate system can be obtained. As described above, according to the substrate inspection apparatus 10 of the first embodiment, the semiconductor wafer 11 is rotated about the center 11e at intervals of 90 degrees, and when the rotation is stopped, the semiconductor wafer 11 is translated in the uv direction. Therefore, the movable ranges Δu and Δv (FIG. 6) in the horizontal plane (uv plane) can be set to the same extent as the radius r of the semiconductor wafer 11.

Therefore, the bottom surface dimension of the holder driving section (14-16) can be reduced to about 1.5 times the diameter of the semiconductor wafer 11. As a result, the substrate inspection apparatus 10 can be downsized. Also, let the diameter of the semiconductor wafer 11 be Δ
When φ is increased, holder drive (14-16)
Although the bottom dimension of the holder must be increased, in the board inspection apparatus 10 of the first embodiment, the holder drive unit (14 to 16)
The increment of the bottom area of "(1.5) ² · ((φ + Δφ) ² −φ ² ) =
Incremental “8φ · Δφ + 4Δ” when the stroke is increased to about 4.5φ / Δφ + 2.25Δφ ² ”
It can be kept small compared to φ ² ”. For example,
When φ = 200 mm and Δφ = 100 mm, the increment by the substrate inspection apparatus 10 of the first embodiment is 112500 mm ^2.
And the conventional increment is 200,000 mm ² .

Furthermore, the substrate inspection apparatus 10 of the first embodiment
Since the semiconductor wafer 11 is rotated at 90 ° intervals, the circuit pattern 11 formed on the semiconductor wafer 11 is
The linear directions of b and 11c (FIGS. 2 to 5) can always be kept parallel to the u direction or the v direction of the uv coordinate system. That is, the linear directions of the circuit patterns 11b and 11c are not inclined with respect to the u direction or the v direction of the uv coordinate system.

Therefore, each quadrant of the semiconductor wafer 11 is
The pattern image can be captured from (51 to 54) under the condition that the relationship between the pattern and the pixel is the same, and each quadrant (51 to 54)
It is possible to inspect the circuit patterns 11b and 11c formed on the substrate with the same accuracy. Further, in the substrate inspection apparatus 10 of the first embodiment, the boundary portions of the quadrants (51 to 54) are overlapped to capture a pattern image, and the quadrants are corrected while correcting the rotation axis deviation and the rotation amount error of the wafer holder 12. In order to capture the pattern image of (51-54), each quadrant
It is possible to capture a good pattern image with no deviation in the boundary portion of (51 to 54).

In the above-described first embodiment, which quadrant (51 to 54) is the target of image capture when the semiconductor wafer 11 is translated in the uv direction while the rotation of the semiconductor wafer 11 is stopped. Regardless of this, an example has been described in which the pattern image is always taken in during parallel movement in the u direction (FIG. 9), but the present invention is not limited to this configuration. In addition, when the first quadrant 51 is the target of image capture (see FIG. 10).
(a)) and the third quadrant 53 are the target of image capturing (FIG. 10 (c)), the pattern image is captured during the parallel movement in the v direction, and the second quadrant 52 is the target of image capturing. In case of (FIG. 10 (b)) and in case of the fourth quadrant 54 being the object of image capturing (FIG. 10 (d)), the pattern image is captured during the parallel movement in the u direction. , A configuration in which the quadrants (51 to 54) are sequentially switched can be considered.

According to this structure, the direction of parallel movement when capturing the pattern image is constant with respect to the xy coordinate system of the semiconductor wafer 11. That is, the scanning direction on the surface of the semiconductor wafer 11 is constant regardless of the quadrants (51 to 54). Therefore, the pattern image can be efficiently reconstructed, and the accuracy of the reconstructed overall pattern image is improved.

Further, instead of switching the direction of parallel movement when capturing the pattern image for each quadrant (51 to 54), the reading direction of the two-dimensional image pickup device 28 is changed to each quadrant (51).
Up to 54). In this case, since the signal of the pattern image uniformly enters the half of the semiconductor wafer 11 to the image processing unit 29, complicated coordinate conversion is unnecessary.

(Second Embodiment) The second embodiment of the present invention is
It corresponds to claims 1 to 4. Here, an example will be described in which the substrate inspection apparatus 10 described above is used to capture an image of a specified overlay mark on the surface of the semiconductor wafer 11 in order to perform an overlay inspection on the semiconductor wafer 11.

The overlay mark is a mark indicating the overlay state of the resist pattern on the base pattern formed on the surface of the semiconductor wafer 11, and is usually composed of an outer rectangular mark and an inner rectangular mark. Also,
The overlay marks are generally formed at the four corners of each shot area 11a of the semiconductor wafer 11 (FIG. 2).
The basic operation for capturing an image is the same as steps S1 to S7 in FIG. 8 described above. When the semiconductor wafer 11 is stopped in the rotating state in FIG. Overlay mark 71 in quadrant 51
(FIG. 11A) is positioned within the imaging area, and the pattern image of the overlay mark 71 is captured by the image processing unit 29. The image processing unit 29 performs the positioning control.

Then, similarly, the semiconductor wafer 11 is formed as shown in FIG.
When it is stopped in the rotating state, the registration mark 72 (FIG. 11B) in the second quadrant 52 is positioned within the imaging area, and the pattern image of the registration mark 72 is displayed in the image processing unit 29. take in. Furthermore, when the semiconductor wafer 11 is stopped in the rotating state shown in FIGS.
The overlay marks 73 and 74 (FIGS. 11C and 11D) in the third and fourth quadrants 54 are positioned within the imaging area, and the pattern image of each overlay mark 73 and 74 is transferred to the image processing unit 29. Take in.

In this way, each quadrant of the semiconductor wafer 11 is
When the pattern images of the overlay marks 71 to 74 are fetched from (51 to 54), the image processing unit 29 sets the center coordinates (x ₁ , y ₁ ) of the outer rectangular mark in each of the overlay marks 71 to 74. Center coordinates of the inner rectangular mark (x ₂ , y
₂ ) The positional shift amount and the positional shift direction are calculated as the overlay shift amount (Δx, Δy). The amount of overlay deviation is
It is represented as a two-dimensional vector on the surface of the semiconductor wafer 11.

In addition, the amount of overlay deviation as described above
After calculating (Δx, Δy), this overlay displacement (Δ
x, Δy) is corrected using a correction value called TIS (Tool Induced Shift). The TIS is a measurement error caused by an apparatus that cannot be driven in when adjusting the substrate inspection apparatus 10, and a different value is used for each processing step of the semiconductor wafer 11.

Here, in the substrate inspection apparatus 10, the TI
The operation for determining the value of S will be described. First, when the semiconductor wafer 11 is stopped in the rotating state of FIG. 2, the pattern image of the overlay mark 75 (FIG. 12A) located near the center 11e of the semiconductor wafer 11 is captured, and then the semiconductor wafer 11 11 is rotated 180 degrees, and the pattern image of the same overlay mark 75 (FIG. 12B) is captured.

Then, the image processing unit 29 calculates the overlay deviation amount (Δx ₀ , Δy ₀ ) based on the pattern image of the overlay mark 75 captured in the state of FIG. Based on the pattern image of the overlay mark 75 captured in the state of b), the overlay shift amount (Δ
x ₁₈₀ , Δy ₁₈₀ ) is calculated, and the average value of these two overlay displacement amounts is determined as the TIS value (TISu, TISv).

TISu is a measurement error in the u direction of the substrate inspection apparatus 10, and TISv is a measurement error in the v direction. Next, the board inspection apparatus 1 determined as described above
Using the TIS value of 0 (TISu, TISv), the overlay deviation amount (Δx, Δ) of the overlay marks 71 to 74 (FIG. 11) in each quadrant (51 to 54) of the semiconductor wafer 11
The process of correcting y) will be described.

The correction process using the TIS values (TISu, TISv) is performed in consideration of the orientation of the xy coordinate system when the pattern image is taken in from the semiconductor wafer 11. As shown in FIG. 11A, when the pattern image in the first quadrant 51 is captured, the azimuth of the xy coordinate system with respect to the uv coordinate system has a relationship of (+ x, + y) = (+ u, + v). In addition, when the pattern image of the second quadrant 52 is captured, uv
The orientation of the xy coordinate system with respect to the coordinate system is (+ x, + y) = (-
v, + u).

Furthermore, when the pattern image of the third quadrant 53 is taken in, the orientation of the xy coordinate system with respect to the uv coordinate system is
(+ X, + y) = (-u, -v). Further, when the pattern image of the fourth quadrant 54 is captured, the azimuth of the xy coordinate system with respect to the uv coordinate system is (+ x, + y) = (+ v,-
u). Therefore, the semiconductor wafer 11
Registration marks 71-in each quadrant (51-54) of
In order to correct the overlay deviation amount (Δx, Δy) of 74 (FIG. 11), the orientation of the xy coordinate system in each of the above quadrants (51 to 54) is taken into consideration as shown in Table 1 below. Further, the correction value Hx for the overlay deviation amount Δx in the x direction and the correction value Hy for the overlay deviation amount Δy in the y direction are set.

[Table 1] Then, using the correction values Hx and Hy shown in Table 1, each quadrant
By correcting the overlay displacement amount (Δx, Δy) of (51 to 54), the TISu in the u direction, which is a measurement error caused by the device, is corrected.
And TISv in the v direction can be corrected to obtain an accurate overlay deviation amount (ΔX, ΔY) (ΔX = Δx + H
x, ΔY = Δy + Hy). In the embodiment described above, the wafer holder 12 is moved in parallel in the uv direction with respect to the fixed optical system (26, 27, ...), so that the quadrant corresponding to ¼ of the semiconductor wafer 11 Although the example of capturing the pattern image has been described, the present invention is not limited to this configuration.

Besides, by fixing the wafer holder 12 and moving the optical system (26, 27, ...) In parallel in the uv direction,
A pattern image may be captured from one quadrant of the semiconductor wafer 11. Further, the parallel movement of the wafer holder 12 and the parallel movement of the optical system (26, 27, ...) May be combined to capture the pattern image from one quadrant of the semiconductor wafer 11.

Further, in the above-described embodiment, an example (FIG. 8) in which the pattern image of each quadrant (51 to 54) is captured while correcting the rotational axis deviation and the rotation amount error of the wafer holder 12 has been described. Is not limited to this procedure. In addition, when the pattern images of all quadrants (51 to 54) are taken in by the procedure omitting step S7 of FIG. 8 and the pattern images are reconstructed in step S8,
The image data shift correction may be performed using the position correction amount calculated in 6.

Further, in the above-described embodiment, the two-dimensional image pickup device 28 has a structure in which a plurality of pixels are arranged in a square lattice, but in the present invention, a plurality of pixels are arranged in a triangular lattice. Also, it can be applied to a two-dimensional image pickup device and a two-dimensional image pickup device arranged in a hexagonal lattice. At this time, it is desirable to set the rotation step to 60 ° or 30 ° so that the image detection direction and the pixel direction match.

In the above embodiment, the autofocus mechanism (focusing unit (30 to 41)) for measuring the gap between the slit images divided into the pupils to detect the amount of defocus is described. The amount of defocus is detected by projecting obliquely, and the wafer holder 12 is moved by an amount corresponding to the defocus amount.
Slit image projection method for moving up and down, and wafer holder 12
It is also possible to use an image processing method or the like in which is moved in the z direction to position the z position where the contrast of the captured image is maximum as the focus position.

[0072]

As described above, according to the present invention,
Since it is possible to reliably suppress the increase in the size of the device due to the increase in the size of the substrate, it is possible to avoid the increase in the size of the clean room, and as a result, it is possible to reduce the cost and deal with the miniaturization of the circuit pattern.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a board inspection apparatus 10 according to a first embodiment.

FIG. 2 is a diagram illustrating a semiconductor wafer 11 (rotation angle 0 °).

FIG. 3 is a diagram illustrating a semiconductor wafer 11 (rotation angle 90 degrees).

FIG. 4 is a diagram illustrating a semiconductor wafer 11 (rotation angle 180 degrees).

FIG. 5 is a diagram illustrating a semiconductor wafer 11 (rotation angle 270 degrees).

FIG. 6 is a diagram illustrating a movable range of a wafer holder 12.

FIG. 7 is a diagram illustrating four quadrants in the semiconductor wafer 11.

FIG. 8 is a flowchart showing a procedure of an image capturing operation in the board inspection device 10.

FIG. 9 is a diagram illustrating an operation of capturing a pattern image from four quadrants of the semiconductor wafer 11.

FIG. 10 is a diagram illustrating another operation for capturing a pattern image from the four quadrants of the semiconductor wafer 11.

11 is a diagram showing overlay marks formed in four quadrants of the semiconductor wafer 11. FIG.

FIG. 12 is a diagram illustrating an operation for determining a TIS value of the board inspection apparatus 10.

[Explanation of symbols]

10 Board inspection device 11 Semiconductor wafer 12 Wafer holder 14 u drive 15v drive 16 rotary drive 26 Objective Lens 27 Imaging lens 28 Two-dimensional image sensor 29 Image processing unit

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) // G01R 31/02 H01L 21/30 502V F term (reference) 2F065 AA03 BB02 BB03 BB27 CC19 DD02 FF04 JJ03 JJ09 JJ25 JJ26 LL04 LL12 LL22 LL30 LL46 MM02 MM03 PP12 QQ31 2G014 AA00 AB59 AC09 2G051 AA51 AB01 AB02 AB10 BB07 BB09 BB15 CA03 CB01 CB05 CC11 CC12 DA07 DA08 DA09 DA15 EA12 ED11 ED12 DB12 DB11 DB12 DJ11 DB12 DB04 DB11 DB12

Claims (4)

[Claims] 1. An optical system for forming an image of a partial area on a surface to be inspected of a substrate, and an axis passing through the center of the surface to be inspected and perpendicular to the surface to be inspected as a rotation axis, the substrate is 90 degrees. Rotation means for rotating at intervals, and parallel movement means for relatively moving the substrate and the optical system in parallel along the surface to be inspected while the rotation of the substrate by the rotation means is stopped. Substrate inspection device characterized by. 2. The substrate inspection apparatus according to claim 1, wherein the parallel moving unit relatively moves the substrate and the optical system in parallel within a range corresponding to one quadrant of the surface to be inspected. A substrate inspection apparatus characterized by: 3. The substrate inspection apparatus according to claim 1 or 2, wherein the rotating means and the parallel moving means are controlled to show an overlapping state of a plurality of pattern layers provided on the surface to be inspected. Positioning means for positioning the mark within the field of view of the optical system, and detection means for capturing the image of the mark formed by the optical system as an image and detecting the overlapping state based on the image Substrate inspection device characterized by. 4. A step of rotating the substrate at 90-degree intervals with an axis passing through the center of the surface to be inspected of the substrate and being perpendicular to the surface to be inspected as a rotation axis, the rotation of the substrate being stopped. A substrate inspection method, comprising: an optical system that forms an image of a partial area on a surface to be inspected; and a step of relatively moving the substrate in parallel along the surface to be inspected.